1. Field of the Invention
Exemplary embodiments of the invention relate to a liquid crystal display.
2. Discussion of the Related Art
Active matrix type liquid crystal displays display a motion picture using a thin film transistor (TFT) as a switching element. The active matrix type liquid crystal displays have been implemented in televisions as well as display devices in portable devices such as office equipments and computers, because of the thin profile of the active matrix type liquid crystal displays. Accordingly, cathode ray tubes (CRT) are being rapidly replaced by active matrix type liquid crystal displays. The liquid crystal display includes a liquid crystal display panel and a backlight unit irradiating light to the liquid crystal display panel.
Recently, demand for polarized sunglasses is rapidly increasing. The polarized sunglasses polarize diffusively reflected natural light. A user wearing the polarized sunglasses can clearly see an object through the polarized sunglasses without glitter. Accordingly, the polarized sunglasses may help the user to safely drive and protect his or her eyes in outdoor activities.
When the user wearing the polarized sunglasses sees an image displayed on the liquid crystal display, there is the case where the user wearing the polarized sunglasses cannot see the image displayed on the liquid crystal display. For example, as shown in FIG. 1, when a light absorption axis 11 of an upper polarizing plate (or analyzer) 10 of a liquid crystal display panel and a light absorption axis 13 of polarized sunglasses 12 form a right angle (i.e., 90°), the polarized sunglasses 12 do not transmit light passing through the upper polarizing plate 10 of the liquid crystal display panel. As shown in FIG. 2, when the light absorption axis 11 of the upper polarizing plate 10 of the liquid crystal display panel and the light absorption axis 13 of the polarized sunglasses 12 meet each other, the polarized sunglasses 12 may transmit light passing through the upper polarizing plate 10 of the liquid crystal display panel. Accordingly, a method has been required to see the image displayed on the liquid crystal display panel through the polarized sunglasses 12 irrespective of an angle between the light absorption axis 11 of the upper polarizing plate 10 of the liquid crystal display panel and the light absorption axis 13 of the polarized sunglasses 12. For this, a polarization compensation film may be added to the upper polarizing plate 10 of the liquid crystal display panel. In this case, a thickness of the upper polarizing plate 10 may increase. If a difference between the thickness of the upper polarizing plate 10 and a thickness of a lower polarizing plate (not shown) of the liquid crystal display panel increases, the liquid crystal display panel may be bent because of a difference between residual stresses of upper and lower substrates of the liquid crystal display panel.